JP2014009333A - Rubber composition, and vulcanization rubber product and hose using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition having excellent durability to an external environment; and a vulcanization rubber product and a hose using the same.SOLUTION: A rubber composition includes: a rubber constituent (A); a water repellency agent (B); and hydrotalcite (C), wherein the rubber constituent (A) includes one or both of CR and SBR, the water repellency agent (B) includes an ultrahigh-molecular weight polyethylene powder; and one or one or more of a fatty acid amide compound, the sum content of each component of the water repellency agent (B) is at least 2 parts by mass and at most 30 parts by mass based on 100 parts by mass of the rubber constituent (A), and a content of the hydrotalcite (C) is at least 2 parts by mass and at most 20 parts by mass based on 100 parts by mass of the rubber constituent (A).

Description

  The present invention relates to a rubber composition and a vulcanized rubber product and a hose using the rubber composition, and more particularly, in a hose having a brass-plated reinforcing layer such as a brass-plated wire such as a hydraulic hose, The present invention relates to a rubber composition and a hose using the rubber composition, which have greatly improved durability against the external environment by alleviating corrosion of the rubber.

  The hydraulic hose has a rubber inner layer that is resistant to erosion to fluid, a surface that is placed adjacent to the outer peripheral side of the rubber inner layer is brass-plated, and a reinforcing layer that improves pressure resistance, and an outer peripheral side of the reinforcing layer. And an outer rubber layer. The outer layer rubber of the hydraulic hose is required to have oil resistance and weather resistance (particularly ozone resistance). Moreover, since these hoses often have a brass-plated reinforcing layer such as a brass-plated (Cu—Zn alloy) wire, the rubber composition applied to the outer layer rubber is vulcanized and bonded to a metal such as brass. Sex is also required.

  For this reason, conventionally, a rubber mainly composed of chloroprene rubber (CR), which is excellent in oil resistance, weather resistance and vulcanization adhesiveness with a brass-plated wire, is used as an outer layer rubber of a hydraulic hose. .

  A rubber composition containing a rubber containing CR as a main component, a butadiene-based polymer containing at least a 1,3-butadiene monomer unit as a rubber component, and CR, and each 100 parts by weight of the rubber component A rubber composition for a hose jacket blended in a predetermined amount has been proposed (see, for example, Patent Document 1).

  In addition to CR, as a rubber component for improving oil resistance and weather resistance, a rubber composition for hose jackets containing ethylene-propylene-nonconjugated diene rubber (EPDM) and acrylonitrile-butadiene rubber (NBR) in a predetermined ratio, respectively. It has been proposed (see, for example, Patent Documents 2 and 3).

  Also, when a hydraulic hose is used in a harbor area where there is a large environmental impact such as salt damage, for example, the boundary between the hose outer layer and the reinforcing layer is sealed to prevent rainwater from entering the hose outer layer. It is made to suppress (for example, refer patent document 4).

JP 2010-121006 A JP 2005-188607 A Japanese Patent No. 4299881 JP-A-8-75067

  Here, a hydraulic hose placed in a harbor area or the like is susceptible to salt damage caused by salt water because heavy machinery using hydraulic pressure comes into contact with salt water such as sea water. As a cause of salt damage, a hydraulic hose, a heavy machine using hydraulic pressure, etc. are directly subjected to salt water. Another cause of salt damage is that the salt scattered in the atmosphere accompanying the sea breeze adheres to and accumulates on the surface of hydraulic hoses, heavy machinery using hydraulics, etc. For example, the salt deposited on the surface of heavy machinery or the like using water dissolves to become water containing salt. Another cause of salt damage is that salt that floats in the atmosphere during rain falls with rain.

  Even if the boundary between the hose outer layer and the reinforcing layer is sealed, it is difficult to suppress the intrusion of salt water such as seawater over a long period of time. Therefore, when salt water adheres to the hose outer layer rubber surface and enters the hose outer layer rubber, chlorine ions react with the brass plating wire, and the brass plating wire is corroded. When rust occurs on the brass plating wire, the strength of the hydraulic hose decreases.

  Further, in order to prevent the burst from occurring due to a decrease in strength of the hydraulic hose, it is necessary to replace the hose with a new hose before the burst occurs in consideration of safety.

  In this way, the hydraulic hose has high weather resistance while maintaining oil resistance even in places where the hydraulic hose tends to deteriorate due to the influence of the external environment such as salt damage, such as harbor districts, and excellent vulcanization adhesion to brass-plated wire There is an increasing demand for rubber compositions having properties. Therefore, the appearance of a rubber composition having high deterioration resistance (durability) against an external environment that is easily affected by the environment is eagerly desired.

  In view of the above problems, an object of the present invention is to provide a rubber composition having excellent durability against an external environment and a vulcanized rubber product and a hose using the rubber composition.

  The inventor of the present invention uses a rubber composition containing a rubber component (A), a water repellent (B), and a hydrotalcite (C) as the rubber component (A) as a chloroprene rubber and a styrene-butadiene rubber. Or ethylene-propylene-non-conjugated diene rubber, acrylonitrile-butadiene rubber and styrene-butadiene rubber, and water repellent (B) using one or more of ultrahigh molecular weight polyethylene powder and fatty acid amide compound as a rubber. By containing a predetermined amount of each of component (A), water repellent (B) and hydrotalcite (C), it has excellent oil resistance, weather resistance and adhesion to brass, and has excellent durability against the external environment. A rubber composition was found. The present invention has been completed based on such knowledge.

The present invention includes the following (1) to (9).
(1) includes a rubber component (A), a water repellent (B), and a hydrotalcite (C),
The rubber component (A) includes one or both of chloroprene rubber and styrene-butadiene rubber,
The water repellent (B) includes one or more of ultrahigh molecular weight polyethylene powder and fatty acid amide compound,
The total content of each component of the water repellent (B) is 2 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the rubber component (A).
Content of the said hydrotalcite (C) is 2 to 20 mass parts with respect to 100 mass parts of said rubber components (A), The rubber composition characterized by the above-mentioned.
(2) including a rubber component (A), a water repellent (B), and a hydrotalcite (C),
The rubber component (A) includes ethylene-propylene-nonconjugated diene rubber, acrylonitrile-butadiene rubber, and styrene-butadiene rubber,
The water repellent (B) includes one or more of ultrahigh molecular weight polyethylene powder and fatty acid amide compound,
The content of ethylene-propylene-nonconjugated diene rubber in the rubber component (A) is 20 parts by mass or more and 35 parts by mass or less, and the content of acrylonitrile-butadiene rubber is 30 parts by mass or more and 50 parts by mass or less. The content of N-butadiene rubber is 25 parts by mass or more and 50 parts by mass or less,
The total content of each component of the water repellent (B) is 2 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the rubber component (A).
Content of the said hydrotalcite (C) is 2 to 20 mass parts with respect to 100 mass parts of said rubber components (A), The rubber composition characterized by the above-mentioned.
(3) When the rubber component (A) contains both chloroprene rubber and styrene-butadiene rubber,
The content of the chloroprene rubber is 40 parts by mass or more and less than 100 parts by mass, and the content of the styrene-butadiene rubber is more than 0 parts by mass and 60 parts by mass or less.
(4) The rubber composition according to any one of (1) to (3), which is a rubber composition for a hose.
(5) A vulcanized rubber product obtained by vulcanizing the rubber composition according to any one of (1) to (4) above.
(6) A rubber layer obtained by vulcanizing the rubber composition according to any one of (1) to (4) above, and a reinforcing layer whose surface adjacent to the rubber layer is plated with brass. The vulcanized rubber product according to (4) above.
(7) The vulcanized rubber product according to the above (5) or (6), which is a hose.
(8) The vulcanized rubber product according to (5) or (6) above, which is a hydraulic hose.
(9) A hose having a rubber inner layer, a reinforcing layer having a brass plated surface disposed adjacent to the outer peripheral side of the rubber inner layer, and a rubber outer layer disposed adjacent to the outer peripheral side of the reinforcing layer. There,
Either or both of the rubber inner layer and the rubber outer layer are composed of the rubber composition according to any one of (1) to (4) above.

The rubber composition of the present invention can have excellent durability against the external environment.
In addition, the vulcanized rubber product and the hose of the present invention use the rubber composition of the present invention as a rubber component, and therefore have excellent durability against the external environment. Can do.

FIG. 1 is a perspective view of each hose layer cut away. FIG. 2 is a perspective view showing each layer of an example of another configuration of the hose by cutting away each layer. FIG. 3 is a plan view showing a part of a rubber layer of a rubber / wire composite including a brass-plated wire inside the rubber layer. FIG. 4 is a view showing a state where the rubber / wire composite is immersed in salt water.

  The present invention will be described in detail below. The present invention is not limited by the following modes for carrying out the invention (hereinafter referred to as embodiments). In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range. Furthermore, the constituent elements disclosed in the following embodiments can be appropriately combined.

<Rubber composition>
The rubber composition according to the present embodiment (hereinafter referred to as “the composition of the present embodiment”) includes a rubber component (A), a water repellent (B), and a hydrotalcite (C). It is a thing.

[Rubber component (A)]
The rubber component (A) is at least one selected from the group consisting of chloroprene rubber (CR), styrene-butadiene rubber (SBR), ethylene-propylene-nonconjugated diene rubber (EPDM), and acrylonitrile-butadiene rubber (NBR). Is included. In the present embodiment, the rubber component (A) includes one or both of CR and SBR, or includes EPDM, NBR, and SBR.

  When the rubber component (A) includes either one of CR and SBR, the content of CR and SBR is not particularly limited. The CR content in the rubber component (A) is preferably 40 parts by mass or more and less than 100 parts by mass. If the CR content is less than 40 parts by mass, the oil resistance becomes insufficient. Moreover, from the viewpoint of providing oil resistance, weather resistance, and wear resistance, the CR content is more preferably 50 parts by mass or more and 80 parts by mass or less, and further preferably 60 parts by mass or more and 70 parts by mass or less.

  SBR is a copolymer of styrene and butadiene, and general SBR can be used without particular limitation. In the case where the rubber component (A) is composed of only SBR or containing any rubber other than CR and SBR, the content of SBR is 60 from the viewpoint of superior vulcanization adhesion with brass. It is preferable that the amount is not less than 100 parts by mass.

  When the rubber component (A) includes both CR and SBR, the content of SBR in the rubber component (A) is preferably more than 0 parts by mass and 60 parts by mass or less. If the SBR content exceeds 60 parts by mass, the oil resistance and weather resistance become insufficient. In addition, the SBR content in the rubber component (A) is 20 parts by mass or more and 50 parts by mass or less from the viewpoint that the SBR content is excellent in oil resistance and weather resistance and is excellent in vulcanization adhesion with brass. More preferably, 20 parts by mass or more and 40 parts by mass or less are more preferable.

  Moreover, when rubber component (A) contains EPDM, NBR, and SBR, content of SBR in rubber component (A) is 25 to 50 mass parts. When the SBR content is less than 20 parts by mass, the vulcanization adhesion with brass becomes insufficient, and when it exceeds 50 parts by mass, the oil resistance and weather resistance become insufficient. In addition, the SBR content in the rubber component (A) is 30 parts by mass or more and 40 parts by mass or less from the viewpoint that the SBR content is excellent in oil resistance and weather resistance and is excellent in vulcanization adhesion with brass. Is preferable, and 35 to 40 mass parts is more preferable.

  EPDM is a terpolymer of ethylene, propylene and diene, and general EPDM can be used without particular limitation.

  When the rubber component (A) contains EPDM, NBR, and SBR, the content of EPDM in the rubber component (A) is 20 parts by mass or more and 35 parts by mass or less. When the content of EPDM is less than 20 parts by mass, the weather resistance becomes insufficient, and when it exceeds 35 parts by mass, the oil resistance becomes insufficient. Moreover, from a viewpoint provided with oil resistance and a weather resistance, 20 mass parts or more and 30 mass parts or less are preferable, and, as for content of EPDM in a rubber component (A), 25 mass parts or more and 30 mass parts or less are more preferable.

  NBR is a copolymer of butadiene and acrylonitrile, and general NBR can be used without any particular limitation. The average bond acrylonitrile amount of NBR is preferably 15% by mass or more and 50% by mass or less, and more preferably 20% by mass or more and 45% by mass from the viewpoint of providing oil resistance and cold resistance.

  When the rubber component (A) contains EPDM, NBR, and SBR, the content of NBR in the rubber component (A) is 30 parts by mass or more and 50 parts by mass or less. When the NBR content is less than 30 parts by mass, the oil resistance becomes insufficient, and when it exceeds 50 parts by mass, the cold resistance becomes insufficient. From the viewpoint of providing oil resistance and cold resistance, the content of NBR in the rubber component (A) is preferably 30 parts by mass or more and 45 parts by mass or less, and more preferably 35 parts by mass or more and 45 parts by mass or less.

  When the rubber component (A) contains either one or both of CR and SBR, the rubber component (A) is a rubber other than CR and SBR (hereinafter “other rubber”) as long as the effects of the present invention are not impaired. Can be included). Examples of other rubbers at this time include natural rubber (NR), epoxidized natural rubber (ENR), isoprene rubber (IR), acrylonitrile-isoprene rubber (NIR), butadiene rubber (BR), NBR, EPDM, and butyl rubber. (IIR) and its halides, hydrogenated nitrile rubber (HNBR), acrylic rubber (ACM), styrene-isoprene-butadiene rubber (SIBR), carboxylated butadiene rubber (XBR), carboxylated nitrile rubber (XNBR), carboxylated Examples thereof include styrene butadiene rubber (XSBR), ethylene-vinyl acetate copolymer (EVM), ethyl acrylate-acrylonitrile copolymer (ANM), and ethyl acrylate-ethylene copolymer (AEM). The content of the other rubber in the rubber component (A) is preferably 30 parts by mass or less, and more preferably 0 part by mass.

  Further, when the rubber component (A) contains EPDM, NBR and SBR, the rubber component (A) is a rubber other than EPDM, NBR and SBR (hereinafter “other rubber”) within a range not impairing the effects of the present invention. Can be included). Examples of other rubbers at this time include natural rubber (NR), epoxidized natural rubber (ENR), isoprene rubber (IR), acrylonitrile-isoprene rubber (NIR), butadiene rubber (BR), butyl rubber (IIR) and Its halides, hydrogenated nitrile rubber (HNBR), acrylic rubber (ACM), styrene-isoprene-butadiene rubber (SIBR), carboxylated butadiene rubber (XBR), carboxylated nitrile rubber (XNBR), carboxylated styrene butadiene rubber ( XSBR), ethylene-vinyl acetate copolymer (EVM), ethyl acrylate-acrylonitrile copolymer (ANM), ethyl acrylate-ethylene copolymer (AEM), and the like. The content of the other rubber in the rubber component (A) is preferably 30 parts by mass or less, and more preferably 0 part by mass.

[Water repellent (B)]
The water repellent agent moves to the surface of the vulcanized rubber and accumulates to increase the surface tension of the rubber composition, thereby forming a surface layer (water repellent film) having good water repellency. For this reason, by including the water repellent (B) in the rubber composition, even when the composition of this embodiment is used as a rubber component for a hose, salt water hardly adheres to the rubber surface, and chlorine ions are not formed inside the rubber. Intrusion can be reduced.

  Examples of the water repellent (B) include ultra high molecular weight polyethylene (UHMWPE) powder, fatty acid amide compounds, dimethylpolysiloxane, dimethyltrimethylpolysiloxane, methylphenylpolysiloxane, and methylhydropolyene poly. Siloxane, etc .; modified polysiloxanes such as epoxy modification, carboxy modification, alcohol modification, etc .; polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-hexa Fluoropropylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-ethylene copolymer, polychlorotrifluoroethylene, polyvinylidene fluoride And polyvinyl fluoride. These may be used singly or in combination of two or more. In the present embodiment, the water repellent (B) is particularly preferably an ultrahigh molecular weight polyethylene powder or a fatty acid amide compound. Ultra high molecular weight polyethylene refers to polyethylene having a viscosity average molecular weight of 1,000,000 or more.

  In the composition of the present embodiment, the content of the water repellent is 2 to 30 parts by mass with respect to 100 parts by mass of the rubber component (A), and the physical properties of the vulcanized rubber product that is a molded product Considering the balance of the water repellent effect, the amount is preferably 5 parts by mass or more and 20 parts by mass or less. When the content of the water repellent is less than 2 parts by mass, the water repellency becomes insufficient, and when the content of the water repellent exceeds 30 parts by mass, the bloom (exuded on the surface) becomes severe. Appearance is poor.

[Hydrotalcite (C)]
Hydrotalcite (C) can be used as a halogen catcher. Examples of the halogen catcher include magnesium oxide and calcium hydroxide in addition to hydrotalcite (C). When a halogen catcher such as hydrotalcite (C) is used as the outermost layer of the rubber component constituting the hose, hydrotalcite (C) is less likely to release halogen once caught, and is excellent in environmental safety. Therefore, when the water repellent (B) and the hydrotalcite (C) are included as rubber components constituting the hose, a small amount of salt water is temporarily formed on the surface of the rubber composition with the water repellent (B). Even when passing through a water-based surface layer (water repellent film), hydrotalcite (C) suppresses the progress of corrosion of the brass-plated wire by catching chlorine ions that are catalysts for the corrosion reaction. Can do.

Hydrotalcite (C) is not particularly limited. Hydrotalcite (C) may be a natural product or a synthetic product. For _{example, Mg 3 ZnAl 2 (OH)} 12 CO 3 · wH 2 O (w represents a positive real _{number.), Mg x Al y (} OH) 2x + 3y-2 CO 3 · wH 2 O ( where, x is 1 10, y is 1 to 10, w is. representing a positive real _{number), Mg x Al y (OH} ) 2x + 3y-2 CO 3 [ where, x is 1 to 10, y represents 1 to 10. For example, Mg _4.3 Al ₂ (OH) _12.6 CO ₃ (trade name: DHT-4A-2, manufactured by Kyowa Chemical Industry Co., Ltd.)], Mg _1-x Al _x O _3.83x (0.2 ≦ x <0.5. Examples thereof include Mg _0.7 Al _0.3 O _1.15 (trade name: KW-2200, manufactured by Kyowa Chemical Industry Co., Ltd.).

Hydrotalcite reacts with an acid (for example, one containing halogen. Here, hydrochloric acid will be described as an example) to catch the halogen as in the following formulas (1) and (2).
Mg _4.3 Al ₂ (OH) _12.6 CO ₃ + 2HCl → Mg _4.3 Al ₂ (OH) _12.6 Cl ₂ + H ₂ O + CO ₂ (1)
Mg _0.7 Al _0.3 O _1.15 + 0.3HCl + 0.85H ₂ O → Mg _0.7 Al _0.3 (OH) ₂ Cl _0.3 (2)

  Halogen caught in the hydrotalcite (C) and contained in the reaction product is not released from the reaction product unless the reaction product is heated to 450 ° C. or higher and decomposed. The maximum operating temperature of a hose such as a hydraulic hose is about 180 ° C. When the composition of this embodiment is used as a rubber component constituting these hoses as a hydraulic hose in a harbor area or the like, the halogen once caught is not released again. There are advantages. Also from this point, it is preferable that hydrotalcite (C) is included as an acid acceptor in the composition of the present embodiment.

Among hydrotalcites (C), from the viewpoint of higher halogen catching ability, hydrotalcite having a small amount of hydroxyl groups (OH groups), Mg _1-x Al _x O _3.83x is preferred, Mg _0.7 Al _0.3 O _1.15 is more preferred. Hydrotalcite having a small amount of OH groups in the chemical structure can be produced, for example, by calcining hydrotalcite obtained by synthesis at a higher temperature.

  A commercial item can be used as a hydrotalcite. As a commercial product of hydrotalcite, for example, DHT series manufactured by Kyowa Chemical Industry Co., Ltd. (DHT-4A, DHT-4A-2: firing treatment is performed, but KW-2200 of the KW series described later is heated. No, DHT-4C), KW series manufactured by the same company (the grade in which the DHT series is fired at a higher temperature, and the halogen catching ability tends to be higher than the DHT series. KW-2000, KW-2100, KW-2200) , STABIOCE HT series manufactured by Sakai Chemical Industry Co., Ltd.

  Hydrotalcite (C) may be a natural product or a synthetic product. In the case of a synthetic product, examples of its production method include conventionally known methods. As hydrotalcite (C), hydrotalcite that has been subjected to surface treatment or hydrotalcite that has not been subjected to surface treatment (those whose surface is not treated) can be used. Examples of the surface treatment agent used when surface-treating hydrotalcite include fatty acids (including higher fatty acids) and fatty acid esters. The hydrotalcite (C) is preferably a hydrotalcite that has not been surface-treated from the viewpoint that its halogen catching ability is high. Examples of commercially available hydrotalcite that has not been surface-treated include KW-2200 (manufactured by Kyowa Chemical Industry Co., Ltd.) and DHT-4C (manufactured by Kyowa Chemical Industry Co., Ltd.). A hydrotalcite (C) can be used individually or in combination of 2 types or more, respectively.

  In this embodiment, content of hydrotalcite (C) is 2 mass parts or more and 20 mass parts or less with respect to 100 mass parts of rubber components (A). When the content of hydrotalcite (C) is less than 2 parts by mass, the ratio of reacting with chlorine ions decreases. When content of hydrotalcite (C) exceeds 20 mass parts, the viscosity of a rubber composition will rise and it will cause the fall of rubber processability. By making the content of hydrotalcite (C) within the above range, when hydrotalcite (C) is included as the rubber component of the outermost layer constituting the hose, the hose is excellent in the deterioration resistance performance of the outermost layer, and the hose Corrosion of the brass-plated wire of the reinforcing layer contained inside can be suppressed. In addition, the content of hydrotalcite (C) is superior to the deterioration resistance performance of the outermost layer, and is excellent in flexibility (outermost layer and flexibility of the entire hose), with respect to 100 parts by mass of the rubber component (A). 3 parts by mass or more and 15 parts by mass or less is preferable, and 5 parts by mass or more and 15 parts by mass or less is more preferable.

[Vulcanizing agent]
The composition of this embodiment further contains a vulcanizing agent. Examples of the vulcanizing agent include sulfur such as powdered sulfur, precipitated sulfur, highly dispersible sulfur, surface-treated sulfur and insoluble sulfur; and organic sulfur-containing compounds such as dimorpholine disulfide and alkylphenol disulfide. The content of the vulcanizing agent is preferably 0.1 parts by mass or more and 5.0 parts by mass or less, and 1.0 part by mass or more and 3.0 parts by mass or less with respect to 100 parts by mass of the rubber component (A). It is more preferable that

  Moreover, the composition of this embodiment can use an organic peroxide together with the above vulcanizing agent or in place of the above vulcanizing agent. Here, the organic peroxide is not particularly limited as long as it is generally used for rubber crosslinking, but is preferably an organic peroxide in which the crosslinking reaction does not proceed extremely at the processing temperature in the rubber composition. The organic peroxide having a decomposition temperature (temperature at which the half-life is 10 hours) is 80 ° C. or more is more preferable.

  Specific examples of the organic peroxide include dicumyl peroxide, di-t-butyl peroxide, 1,3-bis (t-butylperoxyisopropyl) benzene, 4,4′-di (t -Butylperoxy) n-butyl valeric acid, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane and the like.

  In the present embodiment, the content of the organic peroxide is not particularly limited because it depends on the amount of active oxygen of the organic peroxide, but is 0.5 parts by mass or more with respect to 100 parts by mass of the rubber component (A). 15 parts by mass or less, and preferably 1 part by mass or more and 15 parts by mass or less. When the content of the organic peroxide is within the above range, the resulting rubber composition of the present invention has an appropriate crosslinking density, and good tensile stress and elongation at break.

[Vulcanization accelerator]
The composition of this embodiment preferably further contains a vulcanization accelerator. Examples of the vulcanization accelerator include aldehyde-ammonia vulcanization accelerator, aldehyde-amine vulcanization accelerator, thiourea vulcanization accelerator, guanidine vulcanization accelerator, thiazole vulcanization accelerator, sulfene. Examples include amide type vulcanization accelerators, dithiocarbamate type vulcanization accelerators, and xanthate type vulcanization accelerators. These may be used alone or in combination of two or more. Among these, a sulfenamide vulcanization accelerator is preferable from the viewpoint that the rubber component (A) has good co-vulcanization characteristics and the rubber has the highest mechanical strength.

  Examples of the sulfenamide-based vulcanization accelerator include N-cyclohexyl-2-benzothiazole sulfenamide, Nt-butyl 2-benzothiazole sulfenamide, N, N-diisopropyl-2-benzothiazole sulfenamide. Examples thereof include sulfenamide slow-acting accelerators such as phenamide and N, N-dicyclohexyl-2-benzothiazylsulfenamide.

  The content of the vulcanization accelerator is preferably 0.1 parts by mass or more and 5.0 parts by mass or less, and 1.0 part by mass or more and 3.0 parts by mass with respect to 100 parts by mass of the rubber component (A). The following is more preferable.

  The composition of the present embodiment preferably further contains carbon black. When carbon black is contained, the rubber performance such as the tensile strength and abrasion resistance of the rubber is excellent. Examples of the carbon black include furnace black, acetylene black, ketjen black, and thermal black.

  As furnace black, for example, SAF (Super Abrasion Furnace), ISAF (Intermediate Super Abrasion Furnace), IISAF-HS (Intermediate ISAF-High Fur Eure, FAF, High AF, High AF, High AF). Examples thereof include “Purpose Furnace” and SRF (Semi-Reinforcing Furnace).

  Examples of the thermal black include FT (Fine Thermal) and MT (Medium Thermal).

  The carbon black is preferably ISAF grade carbon black, HAF grade carbon black, FEF grade carbon black, GPF grade carbon black, SRF grade carbon black, FEF grade carbon black, GPF grade in terms of reinforcement and rubber extrusion processability. Carbon black and SRF grade carbon black are more preferable. These may be used alone or in combination of two or more.

  The content of carbon black is preferably 20 parts by mass or more and 150 parts by mass or less, and more preferably 40 parts by mass or more and 90 parts by mass or less with respect to 100 parts by mass of the rubber component (A).

  The rubber composition of the present embodiment includes a reinforcing agent, an antioxidant, a vulcanization activator, a scorch inhibitor, a tackifier, a lubricant, a dispersant, a processing aid, a triazine derivative, a phenol resin, as necessary. Various additives of vulcanized adhesives such as resorcin and organic acid cobalt salts can be blended.

  The method for producing the rubber composition of the present embodiment is not particularly limited. For example, the essential components and optional components other than the vulcanizing agent and the vulcanization accelerator are kneaded for 5 minutes with a 3.4 liter Banbury mixer, When the temperature reaches 160 ° C., it is released into a master batch, to which a vulcanizing agent and a vulcanization accelerator are added, and kneaded with an open roll to obtain the rubber composition of the present invention. Furthermore, the vulcanized rubber product of the present invention can be obtained by vulcanizing the rubber composition under appropriate conditions.

  As described above, the rubber composition of the present embodiment contains the rubber component (A), the water repellent (B), and the hydrotalcite (C) at the specific ratios described above, thereby providing oil resistance. In addition, it has a good balance of weather resistance and excellent adhesion to brass, and has excellent durability against the external environment. Therefore, when the rubber composition of the present embodiment is used as a rubber component of a hydraulic hose, it has excellent durability against the external environment and can be used stably over a long period of time.

  That is, when the rubber composition of the present embodiment is used as a rubber component of a hose containing a reinforcing layer plated with brass on the surface, the surface of the rubber composition is hydrophobized with a water repellent (B). Thus, it is possible to prevent moisture such as salt water from entering the hose from the hose surface. Thereby, while being able to suppress deterioration of a rubber component, it can suppress that rust arises in an internal brass plating wire, Therefore It aims at the lifetime improvement of a hose. And even if cracks occur on the surface of the hose and water enters from the surface, the hydrotalcite (C) catches halogen ions, so that the brass plating wire of the reinforcing layer is rusted by halogen ions. Can be suppressed.

  Therefore, when the rubber composition of this embodiment is used as a rubber component constituting the hydraulic hose, the rubber component has excellent durability against the external environment, and therefore, the corrosion of the brass plating wire of the reinforcing layer of the hydraulic hose is prevented. As a result, the durability of the hose is greatly improved, and the hose can be used stably over a long period of time.

  Since the rubber composition of the present embodiment has excellent characteristics as described above, it can be suitably used as a rubber composition for hoses.

  Further, the rubber composition of the present invention is useful as a rubber material for rubber / metal composite products used in fields where oil resistance and weather resistance are required. In particular, it can be suitably used for an outer rubber layer of a hydraulic hose having a brass-plated pressure-reinforced steel wire layer and an intermediate rubber used between layers of a brass-plated pressure-reinforced steel wire layer.

<Vulcanized rubber products>
Next, the vulcanized rubber product of the present invention will be described. The vulcanized rubber product of this embodiment is not particularly limited as long as it is obtained by vulcanizing the rubber composition of this embodiment described above, but the rubber obtained by vulcanizing the rubber composition of this embodiment. A vulcanized rubber product having a layer and a reinforcing layer whose surface adjacent to the rubber layer is plated with brass is preferable.

  Specific examples of the vulcanized rubber product of the present embodiment include hoses, conveyor belts, fenders, marine hoses, and tires, preferably hoses, and more preferably power shovels and bulldozers. Pressure of hydraulic oil filled in the hose used in hydraulic machinery such as construction machinery, agricultural machinery such as tillage machines and tractors, and other industrial equipment such as hydraulic jacks, hydraulic punchers, hydraulic presses, hydraulic benders, etc. This is a hydraulic hose that conveys the driving force.

[hose]
An example of a preferred embodiment of the hose of the present embodiment will be described with reference to FIG. FIG. 1 is a perspective view of each hose layer cut away. As shown in FIG. 1, the hose 10 of this embodiment has a rubber inner layer 11, a reinforcing layer 12, and a rubber outer layer 13 laminated in this order.

(Rubber layer (rubber inner layer 11, rubber outer layer 13))
The rubber layer is a layer adjacent to the reinforcing layer, and the hose 10 of the present embodiment has a rubber inner layer 11 and a rubber outer layer 13. In the present embodiment, any one or both of the rubber inner layer 11 and the rubber outer layer 13 among the rubber layers are formed using the rubber composition of the present embodiment, and the oil resistance of the hose 10 is determined. In addition, the rubber outer layer 13 can be formed at least using the rubber composition of the present embodiment from the viewpoint of having a good balance of weather resistance and excellent adhesion to brass and having excellent durability against the external environment. preferable.

As a rubber composition used for the rubber inner layer 11 other than the composition of the present embodiment, a suitable rubber composition is appropriately selected from the viewpoint of oil resistance, chemical resistance, processability, and the like. The raw rubber is at least one selected from the group of synthetic rubbers such as NBR, SBR, acrylic rubber, hydrin rubber, ethylene-acrylate copolymer rubber (especially AEM), and hydrogenated acrylonitrile-butadiene copolymer rubber. Examples thereof include rubber compositions containing rubber as a main component. Furthermore, if necessary, a mixture with a thermoplastic resin or a thermoplastic elastomer may be used. The rubber composition used for the rubber inner layer 11 has a 100% modulus (M ₁₀₀ ) after vulcanization of preferably 4 MPa or more and more preferably 5 MPa or more and 20 MPa or less from the viewpoint of excellent durability of the hose. . In the present specification, 100% modulus indicates a value measured according to JIS K6251-2004.

  As the rubber composition used for the rubber outer layer 13, it is preferable to use the rubber composition of the present embodiment, but it has excellent durability against the external environment such as oil resistance, weather resistance, and adhesion between the rubber layer and the reinforcing layer. A suitable rubber composition can be selected and configured from the viewpoint of having properties.

  The raw rubber used in the rubber composition other than the rubber composition of the present embodiment includes butyl copolymer rubber, ethylene-propylene copolymer rubber, EPDM, NBR, SBR, acrylic rubber, NR, BR, ethylene-acrylic. Examples thereof include rubber compositions mainly composed of at least one rubber selected from the group of synthetic rubbers such as acid ester copolymer rubbers (particularly AEM), hydrogenated NBR, and hydrin rubber. Furthermore, if necessary, a mixture with a thermoplastic resin or a thermoplastic elastomer may be used.

The rubber outer layer 13 is a layer provided adjacent to the outer peripheral side of the reinforcing layer 12. The rubber composition used for the rubber outer layer 13 has a 100% modulus (M ₁₀₀ ) after vulcanization of preferably 2 MPa or more and more preferably 3 MPa or more and 15 MPa or less from the viewpoint of excellent durability of the hose 10. preferable.

Further, the rubber composition used for the rubber outer layer 13 has an inclination angle of 15 degrees between the test piece and the wear wheel, a load of 27 N applied to the wear wheel, in accordance with the Akron wear test (Method A) of JIS K6264-22005. It is preferable that the wear volume per 1000 revolutions of the wear wheel, measured under the condition of 75 ± 5 revolutions per minute of the test piece, is 0.2 cm ³ or less.

  The rubber composition used for the rubber outer layer 13 preferably has an expansion coefficient (VC) of 100% or less in the immersion test (IRM903, 80 ° C., 72 hours immersion) of JIS K6258-2003.

  Further, in the hose 10 of the present embodiment, the thickness of the rubber inner layer 11 is preferably 1.0 mm or greater and 4.0 mm or less, and more preferably 1.5 mm or greater and 1.8 mm or less. Similarly, the thickness of the rubber outer layer 13 is preferably 0.5 mm or more and 2.5 mm or less, and more preferably 0.8 mm or more and 1.5 mm or less.

  Moreover, although the rubber inner layer 11 is made into one layer in this embodiment, it is not limited to this, For example, it is good also as a two-layer structure of an innermost layer (inner surface resin layer) and a rubber layer.

(Reinforcing layer)
The reinforcing layer 12 is a layer whose surface disposed adjacent to the outer peripheral side of the rubber inner layer 11 is brass-plated. The reinforcing layer 12 is provided outside the rubber inner layer 11 from the viewpoint of maintaining strength. In the present embodiment, the reinforcing layer 12 may be formed in a blade shape or a spiral shape. Two or more reinforcing layers 12 may be provided. When the reinforcing layer 12 has two or more layers, examples of the rubber composition used for the rubber intermediate layer between the reinforcing layers include NBR, NR, SBR, BR, EPDM, and ethylene-acrylate copolymer rubber (particularly AEM). And a rubber composition mainly composed of at least one rubber selected from the group of synthetic rubbers. Furthermore, if necessary, a mixture with a thermoplastic resin or a thermoplastic elastomer may be used.

  Although the material which forms the reinforcement layer 12 is not specifically limited, For example, metal materials, such as a hard steel wire (For example, a brass plating (Cu-Zn alloy) wire, a zinc plating wire, etc.), are mentioned suitably. The reinforcing layer 12 is preferably brass-plated from the viewpoint of excellent adhesion to the rubber composition of the present embodiment.

  The manufacturing method of the hose 10 of this embodiment having the rubber layer and the reinforcing layer 12 is not particularly limited, and a conventionally known method can be used. An example of the manufacturing method of the hose 10 of this embodiment is demonstrated. First, the rubber composition for the rubber inner layer 11 is extrusion-molded on the outer side of a core body (mandrel) having the same diameter as the hose inner diameter to cover the mandrel, thereby forming the rubber inner layer (inner tube rubber) 11 (inner Tube extrusion process). Next, a reinforcing layer 12 is formed by braiding a predetermined number of brass-plated wires on the outer side of the rubber inner layer 11 formed in the inner tube extrusion step (knitting step), and the composition of this embodiment is placed on the outer side of the reinforcing layer 12. Extrusion molding is performed to form a rubber outer layer (outer rubber) 13 (outer extrusion process). Furthermore, the outer side of the rubber outer layer 13 formed in the outer shell extrusion step is coated with an appropriate resin (resin mold coating step), and this is performed under predetermined conditions (for example, the temperature is 140 ° C. or higher and 190 ° C. or lower and the heating time is 30 minutes. More than 180 minutes), press vulcanization, steam vulcanization, oven vulcanization (hot air vulcanization) or hot water vulcanization for vulcanization adhesion (vulcanization process). After vulcanization, the coating resin is peeled off (resin mold peeling step), and the mandrel is removed (mandrel extraction step) to produce a hydraulic hose having the reinforcing layer 12 between the rubber inner layer 11 and the rubber outer layer 13.

  Note that the hose 10 of the present embodiment has a three-layer structure in which the rubber inner layer 11, the reinforcing layer 12, and the rubber outer layer 13 are sequentially laminated from the inside as described above. The hose 10 may be provided with a plurality of the reinforcing layers 12 and a rubber intermediate layer (intermediate rubber) between the reinforcing layers 12. For example, as shown in FIG. 2, the hose 10 of the present embodiment includes a rubber inner layer 11, a first reinforcing layer 12-1, a rubber intermediate layer 15, a second reinforcing layer 12-2, and a rubber outer layer. 13 in this order from the inside. The structure of the hose 10 of the present embodiment may be adjusted as appropriate according to the required characteristics of the hose and the like.

At this time, the rubber composition used in the rubber intermediate layer 15 is preferably the rubber composition of the present embodiment. The rubber composition used for the rubber intermediate layer 15 preferably has, for example, a 100% modulus (M ₁₀₀ ) after vulcanization of 2 MPa or more.

  The hose 10 of the present embodiment suppresses moisture such as salt water from entering the hose 10 from the outside by forming rubber layers (rubber inner layer 11 and rubber outer layer 13) using the rubber composition of the present embodiment. Since it can do, it can suppress that a rust generate | occur | produces in a brass plating wire and corrosion advances. Therefore, the hose 10 of the present embodiment is excellent in oil resistance and weather resistance, and can maintain adhesiveness to the reinforcing layer 12. Therefore, since the hose 10 of this embodiment has the durability outstanding with respect to the external environment, it can be used stably over a long period of time.

  Moreover, it is easy to receive salt damage caused by salt water such as seawater, such as a hydraulic hose placed in a harbor area. The cause of salt damage is that salt that is directly covered with salt water or scattered in the atmosphere accompanying the sea breeze adheres to the hose surface, then rains and the salt attached to the hose surface dissolves to remove salt. It is caused by contact with the hose surface as it contains water, or when salt that floats in the atmosphere during rain falls with the rain and adheres to the hose surface. As described above, the hose 10 according to the present embodiment is excellent in oil resistance and weather resistance, and can maintain adhesion to the reinforcing layer 12. Even when used as a hose that is susceptible to salt damage caused by the above, a highly reliable hydraulic hose can be provided.

  Hereinafter, the composition of the present embodiment will be specifically described by way of examples. However, this embodiment is not limited to these.

<Examples 1-1 to 1-3, Comparative Examples 1-1 to 1-8>
Examples 1-1 to 1-3, Comparative Examples 1-1 to 1-8
Is a rubber component (A) containing CR and SBR. The components shown in Table 1 below were blended in the proportions (parts by mass) shown in Table 1 below to prepare rubber compositions. Specifically, first, among the components shown in Table 1 below, components excluding sulfur and a vulcanization accelerator are kneaded for 5 minutes with a Banbury mixer (3.4 liters) and released when the temperature reaches 160 ° C. Got a batch. Next, sulfur and a vulcanization accelerator were added to the obtained master batch and kneaded with an open roll to obtain a rubber composition. About each obtained rubber composition, the extrusion process characteristic and external appearance of rubber | gum obtained from a rubber composition were evaluated by the method shown below. Moreover, the corrosion resistance of the rubber / wire composite obtained by using the rubber composition was evaluated. Table 1 shows the addition amount (parts by mass) of each component and the results in each Example and Comparative Example.

(Production of rubber / wire composite)
After including a brass plating (Cu—Zn alloy) wire between unvulcanized rubber sheets of each rubber composition, hot press vulcanization was performed at 148 ° C. for 45 minutes, and as shown in FIG. A vulcanizate (rubber / wire composite 23: 50 mm width × 150 mm length × 5 mm thickness) containing brass-plated wire 22 inside was prepared.
(Preparation of salt water for corrosion test)
Since the average seawater salt concentration was 35 ‰, 35 grams of purified sodium chloride was mixed with 1 liter (1000 milliliters) of distilled water.

[Evaluation of physical properties]
The rubber obtained from each rubber composition was evaluated for the extrusion processing characteristics and appearance. Further, the corrosion resistance of the rubber / wire composite 23 was evaluated. The evaluation results are shown in Table 1.

(Corrosion resistance)
After the obtained rubber / wire composite 23 was placed in a test tank, the inside of the test tank was set to 100 ° C., heated for 72 hours, thermally aged, then taken out from the test tank and allowed to cool to room temperature. Thereafter, as shown in FIG. 4, the rubber / wire composite 23 was immersed in the salt water 26 in the container 25 for a predetermined period (40 ° C., 7 to 28 days). Thereafter, the rubber / wire composite 23 was taken out from the salt water 26. Thereafter, the rubber layer 21 of the rubber / wire composite 23 was peeled off, and the presence or absence of rust on the wire was visually observed. The observation results were evaluated according to the following criteria. The observation results are shown in Table 1. If no rust is found on the wire, it can be said that the corrosion resistance is good.
Judgment standard “○”: No rust on the wire “△”: A small amount of rust on the wire, “X”: A lot of rust on the wire

(Extrusion characteristics)
The obtained unvulcanized rubber was put into an extruder and extruded, and the ease of molding was evaluated according to the following criteria. The results are shown in Table 1. When rubber processing is easy, it can be said that the extrusion characteristics are good.
Judgment standard “○”: easy to process “×”: difficult to process

(appearance)
The surface condition of the rubber after extrusion processing was visually observed and evaluated according to the following criteria. The observation results are shown in Table 1. If there is no abnormality such as cracks or distorted shape on the rubber surface, it can be said that the appearance is good.
“O”: No abnormalities such as cracks and shapes distorted in the molded body “X”: Abnormalities such as cracks and shapes distorted in the molded body are recognized

Each component in Table 1 is as follows.
SBR: “Nipol 1502”, manufactured by Nippon Zeon Co., Ltd., emulsion polymerization SBR, bound styrene content 23.5 mass%, Mooney viscosity ML1 + 4 (100 ° C.) 52
CR: “Denka Chloroprene S-41”, manufactured by Denki Kagaku Kogyo Co., Ltd., Mooney viscosity ML1 + 4 (100 ° C.) 48
・ FEF grade carbon black: “HTC # 100”, manufactured by Nippon Kayaku Carbon ・ Magnesium oxide (MgO): “Kyowa Mag 150”, manufactured by Kyowa Chemical Industry Co., Ltd. ・ Zinc oxide (ZnO): three types of zinc oxide, Zodo Chemical Industrial company, stearic acid: “industrial stearic acid N”, manufactured by Chiba Fatty Acid Co., Ltd., paraffin wax saintite R: manufactured by Seiko Chemical Co., Ltd., paraffin wax sun knock: manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., ozone deterioration inhibitor: ozone non 6C, Seiko Chemical Co., Ltd./Water repellent (B) 1: UHMWPE powder (trade name “Miperon XM-200”, viscosity average molecular weight 2 million, average particle size: 30 μm, manufactured by Mitsui Chemicals)
-Water repellent (B) 2: Fatty acid amide compound (trade name “Armoslip CP Powder”, manufactured by Lion Akzo)
・ Hydrotalcite (C): “DHT-4A”, manufactured by Kyowa Chemical Industry Co., Ltd. ・ Naphthenic oil: Komolex H22, manufactured by Fuji Kosan Co., Ltd. ・ Aroma oil: A-OMIX, manufactured by Sankyo Oil Chemical Co., Ltd. ・ Sulfur: Hosoi Chemical Industrial company-made vulcanization accelerator 1 (tetramethylthiuram monosulfide): Noxeller TS, made by Ouchi Shinsei Chemical Industry Co., Ltd./vulcanization accelerator 2 (diphenylguanidine): Noxeller D, made by Ouchi Shinsei Chemical Industry Co., Ltd.

  As is apparent from the results shown in Table 1, a rubber / wire composite produced using a rubber composition that does not contain both the water repellent (B) and the hydrotalcite (C) or does not contain at least one of them. 23 (Comparative Examples 1-1 to 1-5) did not have sufficient corrosion resistance. Further, even in the rubber / wire composite 23 (Comparative Examples 1-6 to 1-8) prepared using a rubber composition containing both the water repellent (B) and the hydrotalcite (C), the water repellent is used. When the content of at least one of (B) and hydrotalcite (C) is too much or too little, any of corrosion resistance, extrusion processing characteristics, and appearance is not sufficient. That is, in the rubber / wire composite 23 (Comparative Example 1-6) produced using a rubber composition having a low content of both the water repellent (B) and the hydrotalcite (C), the corrosion resistance is not sufficient. There wasn't. Further, the rubber / wire composite body 23 (Comparative Example 1-7) produced using the rubber composition containing a large amount of the water repellent (B) had corrosion resistance, but the rubber appearance was insufficient. Further, the rubber / wire composite 23 (Comparative Example 1-8) produced using a rubber composition containing a large amount of hydrotalcite (C) had corrosion resistance, but rubber processability was insufficient. .

  On the other hand, the rubber / wire composites 23 (Examples 1-1 to 1-3) produced using a rubber composition containing a predetermined amount of both the water repellent (B) and the hydrotalcite (C) are corrosion resistant. Extrusion characteristics and appearance were both excellent.

  Therefore, the vulcanizate using the rubber composition containing the rubber component (A), the water repellent (B), and the hydrotalcite (C) and containing each of the specific ratios described above has weather resistance. It was confirmed that it was high, could maintain the adhesion to brass, and had excellent durability against the external environment. It can be said that this is because the salt water 26 can be prevented from entering from the surface of the rubber layer 21, and the occurrence of rust on the brass plating wire 22 inside the rubber layer 21 can be suppressed.

<Examples 2-1 to 2-3, Comparative Examples 2-1 to 2-8>
In Examples 2-1 to 2-3 and Comparative Examples 2-1 to 2-8, rubber components (A) containing EPDM, NBR, and SBR are used. The production method of each rubber composition is the same as that described in the above “Examples 1-1 to 1-3, Comparative Examples 1-1 to 1-8”. Table 2 shows the addition amount (parts by mass) of each component and the results in each Example and Comparative Example.

(Production of rubber / wire composite)
The method for producing a rubber / wire composite produced using each rubber composition is the same as that described in the above “Examples 1-1 to 1-3, Comparative Examples 1-1 to 1-8”. .

[Evaluation of physical properties]
The processability and appearance of the rubber obtained using each of the obtained rubber compositions and the corrosion resistance of the rubber / wire composite 23 are described above in “Examples 1-1 to 1-3, Comparative Examples 1-1 to 1-8”. The corrosion resistance, workability, and appearance were evaluated in the same manner as described above.

(Processability)
It carried out similarly to the above-mentioned "Examples 1-1 to 1-3, Comparative Examples 1-1 to 1-8". The results are shown in Table 2.

(appearance)
It carried out similarly to the above-mentioned "Examples 1-1 to 1-3, Comparative Examples 1-1 to 1-8". The results are shown in Table 2.

Each component in Table 2 is as follows.
SBR: Nipol 1502, manufactured by Nippon Zeon Co., Ltd., emulsion polymerization SBR, bound styrene content 23.5% by mass, Mooney viscosity ML1 + 4 (100 ° C.) 52
NBR: Perbunan 2845F, manufactured by LANXESS, acrylonitrile content 28% by mass, Mooney viscosity ML1 + 4 (100 ° C.) 45
EPDM: EPT 4070, manufactured by Mitsui Chemicals, ethylene content 54 mass%, ethylidene norbornene content 9 mass%, Mooney viscosity ML1 + 4 (125 ° C.) 47
-ISAF grade carbon black: Show Black N220, manufactured by Showa Cabot Co., Ltd.- Zinc oxide: Three types of zinc oxide, manufactured by Shodo Chemical Industry Co., Ltd.- Stearic acid: "Industrial stearic acid N", manufactured by Chiba Fatty Acid Co., Ltd.- Paraffin wax saintite R: Seiko Chemical Co., Ltd., paraffin wax sun knock: Ouchi Shinsei Chemical Co., Ltd., ozone degradation inhibitor: Ozone Non 6C, Seiko Chemical Co., Ltd., water repellent (B) 1: UHMWPE powder (trade name “Miperon XM- 200 ”, viscosity average molecular weight 2 million, average particle size: 30 μm, manufactured by Mitsui Chemicals, Inc.)
-Water repellent (B) 2: Fatty acid amide compound (trade name “Armoslip CP Powder”, manufactured by Lion Akzo)
Hydrotalcite (C): DHT-4A, manufactured by Kyowa Chemical Industry Co., Ltd. Plasticizer DOA: DIACIZER DOA, manufactured by Mitsubishi Kasei Vinyl Co., Ltd. Aroma oil: A-OMIX, Sankyo Oil Chemical Co., Ltd. Sulfur: Hosoi Chemical Industry・ Vulcanization accelerator 3 (Nt-butylbenzothiazole-2-sulfenamide): Noxeller NS-P, manufactured by Ouchi Shinsei Chemical Co., Ltd./Scorch inhibitor: N-cyclohexylthiophthalimide, manufactured by FLEXSYS

  As is clear from the results shown in Table 2, a rubber / wire composite produced using a rubber composition that does not contain both the water repellent (B) and the hydrotalcite (C) or does not contain at least one of them. 23 (Comparative Examples 2-1 to 2-5) did not have sufficient corrosion resistance. Further, even in the rubber / wire composite 23 (Comparative Examples 2-6 to 2-8) produced using a rubber composition containing both the water repellent (B) and the hydrotalcite (C), the water repellent is used. When the content of at least one of (B) and hydrotalcite (C) is too much or too little, any of corrosion resistance, extrusion processing characteristics, and appearance is not sufficient. That is, in the rubber / wire composite 23 (Comparative Example 2-6) produced using a rubber composition having a low content of both the water repellent (B) and the hydrotalcite (C), the corrosion resistance is not sufficient. There wasn't. Further, the rubber / wire composite 23 (Comparative Example 2-7) produced using the rubber composition containing a large amount of the water repellent (B) had corrosion resistance, but the rubber appearance was insufficient. In addition, the rubber / wire composite 23 (Comparative Example 2-8) produced using a rubber composition containing a large amount of hydrotalcite (C) had corrosion resistance but had insufficient extrusion characteristics. .

  On the other hand, the rubber / wire composites 23 (Examples 2-1 to 2-3) produced using a rubber composition containing a predetermined amount of both the water repellent (B) and the hydrotalcite (C) are corrosion resistant. Extrusion characteristics and appearance were both excellent.

  Therefore, the vulcanizate using the rubber composition containing the rubber component (A), the water repellent (B), and the hydrotalcite (C) and containing each of the specific ratios described above has weather resistance. It was confirmed that it was high, could maintain the adhesion to brass, and had excellent durability against the external environment. It can be said that this is because the salt water 26 can be prevented from entering from the surface of the rubber layer 21, and the occurrence of rust on the brass plating wire 22 inside the rubber layer 21 can be suppressed.

DESCRIPTION OF SYMBOLS 10 Hose 11 Rubber inner layer 12 Reinforcement layer 12-1 1st reinforcement layer 12-2 2nd reinforcement layer 13 Rubber outer layer 15 Rubber intermediate layer 21 Rubber layer 22 Brass plating wire 23 Rubber / wire composite 25 Container 26 Salt water

Claims (9)

Including a rubber component (A), a water repellent (B), and a hydrotalcite (C),
The rubber component (A) includes one or both of chloroprene rubber and styrene-butadiene rubber,
The water repellent (B) includes one or more of ultrahigh molecular weight polyethylene powder and fatty acid amide compound,
The total content of each component of the water repellent (B) is 2 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the rubber component (A).
Content of the said hydrotalcite (C) is 2 to 20 mass parts with respect to 100 mass parts of said rubber components (A), The rubber composition characterized by the above-mentioned. Including a rubber component (A), a water repellent (B), and a hydrotalcite (C),
The rubber component (A) includes ethylene-propylene-nonconjugated diene rubber, acrylonitrile-butadiene rubber, and styrene-butadiene rubber,
The water repellent (B) includes one or more of ultrahigh molecular weight polyethylene powder and fatty acid amide compound,
The content of ethylene-propylene-nonconjugated diene rubber in the rubber component (A) is 20 parts by mass or more and 35 parts by mass or less, and the content of acrylonitrile-butadiene rubber is 30 parts by mass or more and 50 parts by mass or less. The content of N-butadiene rubber is 25 parts by mass or more and 50 parts by mass or less,
The total content of each component of the water repellent (B) is 2 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the rubber component (A).
Content of the said hydrotalcite (C) is 2 to 20 mass parts with respect to 100 mass parts of said rubber components (A), The rubber composition characterized by the above-mentioned. When the rubber component (A) contains both chloroprene rubber and styrene-butadiene rubber,
The rubber composition according to claim 1, wherein the content of the chloroprene rubber is 40 parts by mass or more and less than 100 parts by mass, and the content of the styrene-butadiene rubber is more than 0 parts by mass and 60 parts by mass or less.   The rubber composition according to any one of claims 1 to 3, which is a rubber composition for a hose.   A vulcanized rubber product obtained by vulcanizing the rubber composition according to any one of claims 1 to 4.   The rubber layer obtained by vulcanizing the rubber composition according to any one of claims 1 to 4, and a reinforcing layer whose surface adjacent to the rubber layer is plated with brass. Vulcanized rubber products.   The vulcanized rubber product according to claim 5 or 6, which is a hose.   The vulcanized rubber product according to claim 5 or 6, which is a hydraulic hose. A hose having a rubber inner layer, a reinforcing layer plated with brass on the outer peripheral side of the rubber inner layer, and a rubber outer layer arranged adjacent to the outer peripheral side of the reinforcing layer,
Either or both of the said rubber inner layer and the said rubber outer layer are comprised with the rubber composition as described in any one of Claims 1 thru | or 4.

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